Washing machine and method for operating the washing machine

ABSTRACT

By using separate cold and warm water connections in a washing machine, and by a laundry drum mounted to rotate horizontally and whose drum casing is provided, for the exchange of detergent solution between the laundry drum and the washing tub, with openings formed to act as scoops for the detergent solution in the washing tub, the laundry drum is filled with warm water in a simpler manner and without placing heat-sensitive textiles at risk. The warm water is conducted onto the drum casing from above at a shallow angle during the rotational phase and in a rotation direction. The warm water does not flow into the drum through the openings, but rather into the washing tub over the drum casing, and mixed with the previously introduced cold water there. Therefore, direct contact between the items being washed and the warm water supplied is avoided without complicated conduction systems.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to a washing machine equipped with separate connections for a cold-water supply system and a warm-water supply system, and with a laundry drum that is mounted about an axis of rotation deviating from the vertical. A drum casing is provided with a large number of openings that are formed in such a way that they act as scoops in a preferred direction of rotation of the laundry drum. In the text which follows, the term “detergent solution” is to be understood to mean any type of working liquid which acts on the items being washed during the washing or rinsing process.

Laundry drums having a scooping action which depends on the direction of rotation are described in published, non-prosecuted German patent applications DE 29 41 767 A1 and DE 199 51 743 A1, for example. One typical feature of these laundry drums is the particular shape of the openings provided in the drum casing and their orientation in one of the directions of rotation of the laundry drum. In order to achieve the desired scooping action, these openings are covered in a hood-like manner by the stamped-out formations, or are provided in outwardly directed stamped-out formations of the drum casing.

In washing machines with an additional warm-water connection, the warm water flows in regularly at the operating temperature of the warm-water supply system of, for example, 65° C. This may lead to fibers of delicate textiles being damaged or to the textiles losing their color. There is also the risk of the washing being less successful as a result of direct contact between warm water and dirty laundry. In order to prevent the so-called “burning in” of stains which occurs in the process and to protect temperature-sensitive laundry, it is necessary to ensure that the warm water does not come into direct contact with the items being washed. To this end, the water that is to be supplied has to be brought to a desired lower temperature by warm water and cold water being mixed before it acts on the items being washed. In known appliances, this is done by a mixing regulator or, in a less complicated manner, by the warm water being conducted to the rear wall of the washing tub, which has already been filled with cold water or cold detergent solution, for example via the dispensing tray and a relatively complex hose connection.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a washing machine and a method for operating the washing machine which overcomes the above-mentioned disadvantages of the prior art devices and methods of this general type.

With the foregoing and other objects in view there is provided, in accordance with the invention, a washing machine equipped with separate connections for a cold-water supply system and a warm-water supply system. The washing machine contains a washing tub and a laundry drum mounted within the washing tub about an axis of rotation deviating from a vertical. The laundry drum has a drum casing with a plurality of drum openings. The drum openings are formed to act as scoops in a preferred direction of rotation of the laundry drum. A warm-water inflow is provided and is oriented in relation to the laundry drum such that warm water strikes the drum casing at a shallow angle in the preferred direction of rotation.

The invention is based on the object of directing the inflow of warm water in the washing machine of the type mentioned in the introduction using simple measures in such a way that direct contact between the warm water and the items being washed can be avoided. In the process, outlay on implementing the invention should be kept to a minimum, additional subassemblies or complex line systems should be avoided in particular, and it should be possible to control the process using known methods.

One feature of the invention is that the warm-water inflow is oriented in relation to the laundry drum in such a way that the warm water strikes the drum casing at a shallow angle in the preferred direction of rotation. These simple measures mean it is possible to ensure that direct contact between the warm water and the items being washed is avoided. The lines can be guided in an extremely simple manner in accordance with the invention. The warm-water inflow is controlled in known manner, as is the filling process overall. The additional outlay on programming is therefore minimal.

In accordance with an added feature of the invention, the warm-water inflow has a warm-water distributor with downwardly directed outlet openings directed toward the drum casing at the shallow angle.

In accordance with another feature of the invention, the drum casing has regions including at least one first region and at least one second region. In the first region, the drum openings are oriented opposite the preferred direction of rotation and the first region is separated from the second region. The second region has the drum openings acting as scoops and the drum openings are oriented in the preferred direction of rotation. The drum casing further has a device for ensuring that water conducted into one of the regions is prevented from passing into another of the regions. The device for separating the regions includes at least one bead disposed between the regions and provided in a circumferential direction of the drum casing.

In accordance with a further feature of the invention, the outlet openings of the warm-water distributor are disposed and formed such that water supplied does not flow beyond a width of the regions of the drum casing.

With the foregoing and other objects in view there is further provided, in accordance with the invention a method for controlling an inflow of water into a washing machine as described above. The warm-water inflow is opened only during at least one rotational phase of the laundry drum in the preferred direction of rotation. In addition, the warm-water inflow is opened with a time delay after a cold-water inflow phase.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a washing machine and a method for operating the washing machine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic, sectional view through a laundry drum according to the invention taken along section line 1-1 shown in FIG. 2;

FIG. 2 is a diagrammatic, side view of the outside of a drum casing of a laundry drum according to FIG. 1; and

FIG. 3 is a diagrammatic, side view corresponding to FIG. 2 of the laundry drum according to a second exemplary embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a drum casing 5 of a laundry drum 1. The drum casing 5 is at such a distance from a washing tub 4 that there is space for a large number of regularly distributed openings 6 with stamped-out hoods 15 which are raised out of a surface of the casing 5. In order to produce stamped-out formations (e.g. hoods) 15 of this type, the casing sheet of the laundry drum 1 is simply cut into in the axial direction and bent upward in the outward direction. The stamped-out formations 15 and their openings 6 are oriented perpendicular to a drum axis 3 in the direction of arrow 7. For simplicity, only a section of the drum casing 5 is shown and a drum drive has not been illustrated at all. When the laundry drum 1 turns in the preferred direction of rotation 7, the hood-like stamped-out formations 15 scoop up considerable amounts of detergent solution as they pass through it in the lower region of the washing tub 4, so that the flow of detergent solution into the interior of the drum 1 is assisted and the items being washed are intensively and thoroughly wetted.

The invention assumes that warm water is always supplied only when the drum 1 is moving in the preferred direction of rotation 7. To this end, a non-illustrated inlet valve for warm-water inflow is opened immediately after the rotary movement starts. The amount of warm water to be introduced overall is restricted by the length of time for which the inlet valve is open.

In order to fill the washing tub 4, which surrounds the laundry drum 1, of the washing machine, warm water flows in from above directly onto the drum casing 5 and during the rotational phase of the laundry drum 1 in the preferred direction 7. A warm-water jet 16 is oriented here in such a way that the warm water strikes the drum casing 5 in the direction of rotation 7 of the drum from above at a shallow angle to a tangent T of the drum circumference. The hood-like stamped-out formations 15 act as roofs and conduct the warm-water stream 16 over the stamped-out formations 15 and to the sides of these, and thus also past the openings 6. In a manner assisted by the same direction of the warm-water jet 16 and the direction of rotation 7 of the laundry drum 1, the inflowing warm water cannot directly enter the interior of the drum, instead it flows downward over the casing 5 of the drum 1 and there drips into the washing tub 4, where it mixes with the previously introduced amount of cold water.

Using an iterative method, the washing machine is filled from separate connections for cold water and warm water, and the process is monitored until the desired level of detergent solution is reached, with cold water or cold detergent solution always being supplied in advance. The mixed-water temperature is always controlled from relatively low temperature values to higher temperature values, and this is monitored by a non-illustrated thermal sensor in the washing tub 4. The methods for this are known and can be adapted very easily. The mixed water which has been cooled down to a predetermined temperature passes through the openings 6 into the interior of the laundry drum 1 only when the water level in the washing tub 4 has reached a level at which the drum casing 5 dips into the detergent solution, scoops up detergent solution by the hood-like stamped-out formations 15 when the drum turns, and forces it into the interior of the drum.

In one refinement of the invention, provision is made to conduct the inflow of warm water via a special warm-water distributor 8 in order to prevent splashes arising when warm water flows in, which could reach the laundry loaded in the interior of the drum too early, that is to say when the water is too warm, and thus to exclude a possible source of danger. The warm-water distributor 8 is disposed in the upper region of the washing tub 4, laterally offset to the drum 1 and approximately parallel to the drum axis 3, in such a way that the warm water strikes the drum casing 5 at a shallow angle through the perpendicularly downwardly oriented outlet openings 14 of the warm-water distributor. When the warm-water distributor 8 is correspondingly dimensioned and the outlet openings 14 are disposed in a regular fashion, the warm water can be distributed over the entire width of the drum casing 5 or of the region in which the openings 6 are disposed, this also resulting in the warm water being mixed with the cold water in the washing tub more rapidly.

In order for the idea of the invention to also be applicable to laundry drums 31 which have a scooping action in both directions of rotation when the drum is reversed, that is to say for laundry drums 31 whose lateral surfaces have differently oriented openings 10 and 36, the drum casing 35 is divided into a plurality of adjacent regions 9 and 11 having oppositely oriented openings 10 and 36 in a development of the invention according to FIG. 3. A warm-water distributor 38 is then adapted in such a way that its downwardly directed outlet openings 34 and 37 are disposed in a manner which corresponds to the division of the drum casing 35 into regions. This design measure results in that it is possible to control the flow of warm water in such a way that it strikes only the regions 11 of the drum casing 35 which are moving in the preferred direction of rotation 7.

However, in accordance with the example illustrated in FIG. 3, the warm-water distributor 38 can also be provided with two warm-water supply lines that can be controlled separately from one another, to be precise a line 32 for the outlet openings 34 and a line 39 for the outlet openings 37. However, for simplified illustration, the line 39 is shown on the wrong side of the laundry drum 31 here since the warm-water jets have to be disposed on the opposite side of the laundry drum 31 in order to orient the warm-water jets from the outlet openings 37 in the direction of the stamped-out formations in the region 9. The corresponding warm-water supply line 32 or 39 can then be fed in each direction of rotation of the drum, so that once again only the regions 11 or 9 having the openings 36 or 10 in the drum casing 35, which are respectively directed away, are sprinkled with water.

A circumferential bead 12 is formed between the various regions 9 and 11 in the drum casing 35. The bead 12 can be in raised or—as in the exemplary embodiment—in recessed form. However, it can also form a separation between the regions 9 and 11 by a wider raised or recessed intermediate region in the drum casing 35 and/or by a plurality of beads 12. As a result, the warm water can be prevented from overflowing from one region 11 into the adjacent region 9 having oppositely oriented openings 10, and direct contact between the warm water and the items being washed can thus be prevented in this embodiment of the laundry drum too.

This application claims the priority, under 35 U.S.C. § 119, of German patent application No. 10 2004 030 872.1, filed Jun. 25, 2004; the entire disclosure of the prior application is herewith incorporated by reference. 

1. A washing machine equipped with separate connections for a cold-water supply system and a warm-water supply system, the washing machine comprising: a washing tub; a laundry drum mounted within said washing tub about an axis of rotation deviating from a vertical, said laundry drum having a drum casing with a plurality of drum openings formed therein, said drum openings formed to act as scoops in a preferred direction of rotation of said laundry drum; and a warm-water inflow being oriented in relation to said laundry drum such that warm water strikes said drum casing at a shallow angle in the preferred direction of rotation.
 2. The washing machine according to claim 1, wherein said warm-water inflow has a warm-water distributor with downwardly directed outlet openings formed therein and directed toward said drum casing at the shallow angle.
 3. The washing machine according to claim 2, wherein: said drum casing has regions including at least one first region and at least one second region, in said first region said drum openings are oriented opposite the preferred direction of rotation and said first region is separated from said second region, said second region having said drum openings acting as said scoops being oriented in the preferred direction of rotation; and said drum casing having means for ensuring that water conducted into one of said regions is prevented from passing into another of said regions.
 4. The washing machine according to claim 3, wherein said means for separating said regions include at least one bead disposed between said regions and provided in a circumferential direction of said drum casing.
 5. The washing machine according to claim 3, wherein said outlet openings of said warm-water distributor are disposed and formed such that water supplied does not flow beyond a width of said regions of said drum casing.
 6. A method for controlling an inflow of water into a washing machine having a washing tub and a laundry drum mounted within the washing tub about an axis of rotation deviating from a vertical, the laundry drum having a drum casing with a plurality of drum openings formed therein and acting as scoops in a preferred direction of rotation of the laundry drum, the washing machine further having a warm-water inflow being oriented in relation to the laundry drum such that warm water strikes the drum casing at a shallow angle in the preferred direction of rotation, which comprises the steps of: opening the warm-water inflow only during at least one rotational phase of the laundry drum in the preferred direction of rotation.
 7. The method according to claim 6, which further comprises opening the warm-water inflow with a time delay after a cold-water inflow phase. 